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Information about Extensor Digitorum

Extensor digitorum muscle
Posterior surface of the forearm. Superficial muscles. (Extensor digitorum communis visible at center.)
Transverse section across the wrist and digits. (Ext. dig. communis labeled at bottom center.)
Latinmusculus extensor digitorum
subject #125 451
Origin:lateral epicondyle (common extensor tendon)
Insertion:2nd and 3rd phalanges
Artery:
Nerve:posterior interosseous nerve
Action:extension of hand and fingers
Antagonist:Flexor digitorum superficialis muscle, Flexor digitorum profundus muscle
Dorlands/Elsevier m_22/12548891
The Extensor digitorum (Extensor digitorum communis) arises from the lateral epicondyle of the humerus, by the common tendon; from the intermuscular septa between it and the adjacent muscles, and from the antebrachial fascia.

Origin, insertion, and relations

It divides below into four tendons, which pass, together with that of the Extensor indicis proprius, through a separate compartment of the dorsal carpal ligament, within a mucous sheath.

The tendons then diverge on the back of the hand, and are inserted into the second and third phalanges of the fingers in the following manner.

Opposite the metacarpophalangeal articulation each tendon is bound by fasciculi to the collateral ligaments and serves as the dorsal ligament of this joint; after having crossed the joint, it spreads out into a broad aponeurosis, which covers the dorsal surface of the first phalanx and is reinforced, in this situation, by the tendons of the Interossei and Lumbricalis.

Opposite the first interphalangeal joint this aponeurosis divides into three slips; an intermediate and two collateral: the former is inserted into the base of the second phalanx; and the two collateral, which are continued onward along the sides of the second phalanx, unite by their contiguous margins, and are inserted into the dorsal surface of the last phalanx. As the tendons cross the interphalangeal joints, they furnish them with dorsal ligaments.

The tendon to the index finger is accompanied by the Extensor indicis proprius, which lies on its ulnar side.

On the back of the hand, the tendons to the middle, ring, and little fingers are connected by two obliquely placed bands, one from the third tendon passing downward and lateralward to the second tendon, and the other passing from the same tendon downward and medialward to the fourth.

Occasionally the first tendon is connected to the second by a thin transverse band.

Action

The Extensor digitorum communis extends the phalanges, then the wrist, and finally the elbow.

It acts principally on the proximal phalanges, the middle and terminal phalanges being extended mainly by the Interossei and Lumbricales.

It tends to separate the fingers as it extends them.

See also

Additional images


Bones of left forearm. Posterior aspect.

Tendons of forefinger and vincula tendina.

Cross-section through the middle of the forearm.

Transverse section across distal ends of radius and ulna.

The mucous sheaths of the tendons on the back of the wrist.


External links

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
 •  • [ e]
Muscles of upper limbs
VERTEBRAL COLUMNtrapezius - latissimus dorsi - rhomboid major - rhomboid minor - levator scapulae
THORACIC WALLSpectoralis major - pectoralis minor - subclavius - serratus anterior
SHOULDERdeltoid - rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) - teres major
ARManterior compartment: coracobrachialis - biceps brachii - brachialis
posterior compartment: triceps brachii - anconeus
FOREARManterior compartment: super. - pronator teres - palmaris longus - flexor carpi radialis - flexor carpi ulnaris - flexor digitorum superficialis - deep - pronator quadratus - flexor digitorum profundus - flexor pollicis longus
posterior compartment: super. - mobile wad (brachioradialis, extensor carpi radialis longus and brevis) - extensor digitorum, - extensor digiti minimi - extensor carpi ulnaris - deep - supinator - anatomical snuff box (abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus) - extensor indicis
HANDlateral volar - thenar (opponens pollicis, flexor pollicis brevis, abductor pollicis brevis, adductor pollicis)
medial volar - palmaris brevis - hypothenar (abductor minimi digiti, flexor digiti minimi brevis, opponens digiti minimi)
intermediate - lumbrical - dorsal interossei - palmar interossei
Latin}}} 
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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bold refer to the diagram at right.)

In the skull (8):
  • 1-9. cranium
  • 7. mandible
''In the middle ears (6):
  • malleus
  • incus
  • stapes
In the throat (1):
  • hyoid
In the shoulder girdle (4):
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The lateral epicondyle of the humerus is a small, tuberculated eminence, curved a little forward, and giving attachment to the radial collateral ligament of the elbow-joint, and to a tendon common to the origin of the Supinator and some of the Extensor muscles.
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common extensor tendon is a tendon shared by a number of extensor muscles in the forearm. It attaches to the lateral epicondyle of the humerus.

It serves as the origin (in part) for a number of muscles (largely in the posterior compartment of the forearm:

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bold refer to the diagram at right.)

In the skull (8):
  • 1-9. cranium
  • 7. mandible
''In the middle ears (6):
  • malleus
  • incus
  • stapes
In the throat (1):
  • hyoid
In the shoulder girdle (4):
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Phalanges is commonly given to the bones that form fingers and toes. In primates such as humans and monkeys, the thumb and big toe have two phalanges, while the other fingers and toes consist of three. Phalanges are classified as long bones.
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Arteries are muscular blood vessels that carry blood away from the heart.[1] All arteries, with the exception of the pulmonary and umbilical arteries, carry oxygenated blood.

The circulatory system is extremely important for sustaining life.
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  • Accessory nerve
  • Accessory obturator nerve
  • Alderman's nerve
  • Anococcygeal nerve
  • Ansa cervicalis
  • Anterior interosseous nerve
  • Anterior superior alveolar nerve
  • Aortic plexus
  • Auerbach's plexus
  • Auriculotemporal nerve
  • Axillary nerve

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posterior interosseous nerve (or dorsal interosseous nerve), on the interosseous membrane, in front of the Extensor pollicis longus, to the back of the carpus, where it presents a gangliform enlargement from which filaments are distributed to the ligaments and articulations
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Kinesiology is the scientific study of the anatomy, physiology, and mechanics of body movement, especially in humans. [1] The word kinesiology is derived the Greek "kinesis" (motion) + the suffix -ology or -logy from the greek "logos" or "logia"(meaning a field of study).
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Extension is a movement of a joint. For example, extension is produced by extending the flexed elbow. The arm is now straight; it has been extended. If the head is tilted all the way back, it is said to be extended.

The movement in the opposite directions is called flexion.
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The hands (med./lat.: manus, pl. manūs) are the two intricate, prehensile, multi-fingered body parts normally located at the end of each arm (medically: "terminating each anterior limb/appendage") of a human or other primate.
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A finger is a type of digit, an organ of manipulation and sensation found in the hands of humans and other primates. Normally humans have five digits on each hand (exceptions are polydactyly, hypodactyly and digit loss).
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An antagonist is a kind of muscle that acts in opposition to the movement generated by the agonist and is responsible for returning a limb to its initial position.

Antagonistic pairs in houses

These antagonistic muscles are found in pairs called antagonistic pairs.
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Flexor digitorum superficialis (flexor digitorum sublimis) is an extrinsic flexor muscle of the fingers at the proximal interphalangeal joints. The bulk of the muscle is in the intermediate layer of the anterior compartment of the forearm.
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In human anatomy, the flexor digitorum profundus is a muscle in the forearm that flexes the fingers. It is considered to be an extrinsic muscle because its action is at a different location than the main body of the muscle.
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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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The lateral epicondyle of the humerus is a small, tuberculated eminence, curved a little forward, and giving attachment to the radial collateral ligament of the elbow-joint, and to a tendon common to the origin of the Supinator and some of the Extensor muscles.
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The humerus is a long bone in the arm or fore-legs (animals) that runs from the shoulder to the elbow. On a skeleton, it fits between the scapula and the ulna. It consists of the following three sections:
  • Upper extremity of humerus
  • Body of humerus

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The antebrachial fascia (or antibrachial fascia) continuous above with the brachial fascia, is a dense, membranous investment, which forms a general sheath for the muscles in this region; it is attached, behind, to the olecranon and dorsal border of the ulna, and gives off
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The extensor indicis proprius (Extensor indicis) is a narrow, elongated muscle, placed medial to, and parallel with, the extensor pollicis longus.

Origin and insertion


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The extensor retinaculum (dorsal carpal ligament) is an anatomical term for the thickened part of the antebrachial fascia that holds the tendons of the extensor muscles in place. It is located on the back of the forearm, just to the hand.
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Phalanges is commonly given to the bones that form fingers and toes. In primates such as humans and monkeys, the thumb and big toe have two phalanges, while the other fingers and toes consist of three. Phalanges are classified as long bones.
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The metacarpophalangeal joints (MCP) are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow cavities on the proximal ends of the first phalanges, with the exception of that of the thumb, which presents more of the characters
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Fasciculus can refer to:
  • nervous tissue
  • Arcuate fasciculus
  • Dorsal longitudinal fasciculus

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Phalanges is commonly given to the bones that form fingers and toes. In primates such as humans and monkeys, the thumb and big toe have two phalanges, while the other fingers and toes consist of three. Phalanges are classified as long bones.
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Interossei refer to muscles between the bones. Specific interossei include:
  • Upper limbs
  • Dorsal interossei muscles (hand)
  • Palmar interossei muscles

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Lumbrical can refer to:
  • Lumbrical muscle (hand)
  • Lumbrical muscle (foot)

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The extensor indicis proprius (Extensor indicis) is a narrow, elongated muscle, placed medial to, and parallel with, the extensor pollicis longus.

Origin and insertion


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Ulnar can refer to:
  • Ulnar nerve
  • Ulnar artery
  • Ulna

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